Apparatus for feeding sheets from a stack to a processing machine



Sept. 9, 1969 F. BAYS 3,466,028 APPARATUS FOR FEEDING SHEETS FROM A STACK TO A PROCESSING MACHINE Filed June 20. 1967 3 Sheets-Sheet 1 L LL Q R \R o\ ii --1 hmmmummmlmmwL a. I

INVENTOR xam/J Bags BY D Sept. 9, 1969 F. BAYS A APPARATUS FOR FEEDING SHEETS FROM A STACK TO A PROCESSING MACHINE Filed June 20, 1967 3 Sheets-Shem 2 mvsmon BY fimuml 4y Sept. 9, 1969 F. BAYS 3,466,028

APPARATUS FOR FEEDING SHEETS FROM A STACK TO A PROCESSING MACHINE Filed June 20, 1967 Sheets-Sheet 5 MIME/V70? FAWN/m0 54% United States Patent US. Cl. 271-11 9 Claims ABSTRACT OF THE DISCLOSURE An apparatus for feeding individual sheets or the like from a stack of such sheets to a processing machine which comprises a plurality of lifting means for the sheets disposed above the stack, and at least two transport rolls arranged downstream of the aforesaid stack in the direction of Withdrawal of the individual sheets therefrom, said sheet being movable between such transport rolls. Further, a cross-beam is provided which is mounted to be longitudinally displaceable and at which are arranged the sheet lifting means. Power driven guide means, typically in the form of quadrangular or quadrilaterial guide linkage arrangements, cooperate with the aforementioned cross-beam for displacing the sheet lifting means. The latter, during displacement, conjointly carry out a substantially curve-shaped work stroke consisting of a vertical component and a horizontal component, wherein the uppermost sheet of the stack arrives between the aforesaid transport rolls at the end of such work stroke.

Background of the invention The present invention relates to an improved apparatus for feeding or transporting individual sheets or the like from a stack to a processing machine. The inventive apparatus is generally of the type comprising a number of lifting elements for the sheets arranged above the sheet stack, and further includes at least two transport rolls arranged downstream of such stack in the direction of withdrawal of the individual sheets therefrom, with the sheets being movable between and through the aforesaid transport rolls. Apparatuses of this type serve for transporting or feeding sheet metal plates, paper sheets, cardboard sheets, or similar flat or strip-like material, to the shears, punches or die cutters, power presses, printing presses or similar processing machines. In the context of this application it should be understood that the term sheets is used in its broader sense to generally encompass substantially flat material which can be placed in stack-like configuration.

In known physical constructions of this type the sheets are initially vertically raised by means of suitable suction devices or magnets, and thereafter, are transported by such horizontally to the processing machine. Since the individual movements take place in succession the operating time or work frequency is relatively long.

Summary of the invention Accordingly, it is a primary object of the present invention to provide an improved apparatus for feeding individual sheets from a stack to a processing machine in a manner which overcomes the drawbacks noted above of the prior art structures.

Another, more specific object of the present invention relates to an improved apparatus of the aforementioned type which is capable of operating at increased speed and is particularly suitable for handling most types of sheet material, even relatively large sheet metal plates or the like.

Still a further significant object of this invention relates to an improved apparatus for feeding sheets from a stack in a controlled manner into a desired processing machine, operating at relatively high speed, capable of handling, without damage, the material which is to be fed, manifesting itself through its relatively inexpensive and uncomplicated construction, thereby assuring against undue breakdown and malfunction while permitting ease of operation.

Yet a further important object of this invention relates to an improved feed apparatus for transporting individual sheets from a stack from one location to a further desired location in a highly eflicient manner and with a minimum of lost time.

Generally speaking, in order to achieve these and further objects which will become more readily apparent as the description proceeds, the inventive apparatus is broadly manifested by the features that the lifting elements or means for the sheets are arranged at a crossbeam which is mounted to be longitudinally displaceable. Further, the aforementioned lifting elements or means can be displaced through the agency of power-driven guide means, in the form of so-called quadrangular or quadrilateral guide linkage arrangements disposed in substantially parallelogram configuration. As a result, the lifting means for the sheets, during such displacement, conjointly carry out a substantially curve-shaped wor-k stroke composed of a vertical component and a horizontal component, wherein the uppermost sheet of the stack arrives between the transport rolls at the end of such work stroke.

Owing to the aforementioned quadrangular or quadrilateral guide linkage arrangement, the sheet lifting means are moved along a substantially curve-shaped path so that, in each instance, the uppermost sheet of a stack is displaced in the feed or transport direction. Consequently, the thus displaced uppermost sheet arrives between the transport rolls and owing to the action of the latter is further conveyed or transported. Such motion cycle and the return movement can take place considerably quicker than two successive movements in directions disposed transverse to one another.

Brief description of the drawings The invention will be better understood, and objects other than those set forth above, will become apparent, when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIGURE 1 schematically illustrates a side view of a preferred embodiment of inventive apparatus in operable association with a stack of sheet-like material;

FIGURE 2 schematically depicts, in side view, the suction cups in operable association with the guide means in the form of quadrangular or quadrilateral guide linkage arrangements, and in a lowered position upon the stack;

FIGURE 3 schematically depicts the suction cups and associated guide means of FIGURE 2 in the raised position engaging the uppermost sheet of the stack and feeding such into the transport or feed rolls; and

FIGURE 4 schematically illustrates a plan view of the apparatus of FIGURE 1.

Description of the preferred embodiment Describing now the drawings, and in particular, referring to FIGURES 1 and 4 it will be noticed that the exemplary embodiment of inventive apparatus incorporates a frame structure 1 having bearing blocks 2 and two pairs of transportor withdrawal rolls 3 and 4 which rotate in the direction of the indicated arrows of FIG- URE 1. In this apparatus it may be assumed that the location A represents the front of the machine whereas the other location designated B represents the rear thereof. Identical rod members 5 which are disposed in tandem, in other words behind one another, are sup ported by the bearing blocks 2. A suitable sled member 6 is mounted to be horizontally displaceable, in the direction of the double-headed arrow 7, upon such rod members 5. This sled member 6 carries the unit or equipment by means of which it is possible to always displace the uppermost sheet, such as sheet 32, of the stack 29 in the transport or feed direction, which, in this case, would be at the right end of the machine towards location B and the transport rolls 3, 4.

Further, this sled member 6 is equipped with a substantially horizontal cross-beam 8. A plurality of downwardly depending suction cups 9 are mounted at such cross-beam 8. These suction cups 9 are disposed in a row behind one another, wherefore in FIGURES 1 to 4 only the forwardmost suction cup is visible. A web or bracket member 10 is secured at the central region of the cross-beam 8 and to which there is hingedly connected a piston rod 11. The latter carries a piston 12 which can be displaced to and fro in a suitable pressure cylinder 13. This pressure cylinder 13 is supported at the sled member 6 by means of a bearing or support bracket 14 (FIGURE 1) and can be rocked about the hinge location 15 with respect to the bearing bracket 14.

Continuing, it is to be understood that a respective guide means, generally designated by reference numeral 40 and incorporating so-called quadrangular or quadrilateral guide linkage arrangements, is disposed at each end of the cross-beam 8. The control links 16 and 17 of each such guide means 40 are pivotable about the pivot pins 18 and 19 respectively, as best seen by referring to FIGURES 2. and 3. These pivot pins 18 and 19 are embedded or otherwise afiixed at the horizontally displaceable sled member 6. The cross-beam 8 and a respective bracket 20 afiixed thereto serves as the connecting element for each quadrilateral guide linkage arrangement 40. In this context, it is remarked that the hinge connection of the bracket 20 and the cross-beam 8 to the control links 16 and 17 respectively, is undertaken through the agency of suitable journal pins 21 and 22 respectively (FIGURE 2). Further, it should be observed that the guide means 40 in the form of the quadrangular or quadrilateral guide linkage arrangements are constructed as so-called parallelogram guides. This, in effect, means that the spacing of the pins 18 and 19 is equal to the spacing of the pins 21 and 22, and further, that the spacing of the pins 18 and 21 is equal to the spacing of the pins 19 and 22. Owing to this parallelogram guide arrangement the underface or bottom of the suction cups 9 remains continuously horizontal during their substantially arc-shaped pivoting or rocking about the pins 18. FIGURES 2 and 3 depict the position of the quadrilateral guide linkage arrangements 40 in both terminal positions. Since in these terminal positions the control links 16 and 17 are at the region of their dead-center positions, it is advantageous to employ elastic elements 23 and 24, for instance coil springs, which in the respective terminal positions of the control links 16 and 17 are alternately pre-stressed and serve to assist such control links, during a reversal in movement, to move away from their dead-center position.

Additionally, it will be observed that an elevationally displaceable table means 25 is provided beneath the cross-beam 8. This table means 25 is guided by vertical columns 26 and can be selectively raised and lowered by means of a pressurized fluid medium operated piston unit 27. Further, as shown in FIGURE 1, a pallet 28 with a stack of sheets 29 is located upon the table means 25.

A known magnet beam 30, internally containing a number of non-visible magnets, is secured to the sled member or carriage 6. These magnets serve to separate the stacked uppermost sheet, for instance a sheet metal panel, of the stack 29 from the rest of the stack in a magnetic manner, as is known to the art. Due to these magnets lifting of the uppermost sheet metal plate 32 or the like by means of the suction cups or lifting devices 9 is considerably facilitated. A number of guide ledges 31, advantageously formed of rust-proof steel, protect the magnet beam 30. However, if the sheets do not consist of a magnetic material, for instance are formed of aluminum, paper or cardboard, then stack separation is undertaken by compressed air which flows through suitable nozzles in the conventional manner. It is for these reasons that it is advantageous if the magnet beam 34 is equipped with both separating magnets as well as compressed air nozzles. In order to simplify the illustration in the drawing there have been omitted the electric conductors running to the individual units, also the hydraulic or pneumatic conduits for the pistons 12 and 27 as well as for the suction cups 9, particularly since such structure can be conventional and does not form part of the subject matter of the present invention.

The mode of operation of the heretofore described exemplary embodiment of inventive apparatus is a follows: After depositing a stack of sheets 29 or the like by means of the pallet 28 upon the table means 25 the latter is sufficiently elevated so that the uppermost sheet 32 is situated approximately at the height between the rollers of each pair of transport rolls 3 and 4. The carriage or sled member 6 is displaced along the horizontal rod members 5 in such a manner that the magnet beam 30 is situated at a spacing of several millimeters from the rear of the stacked sheets. Now, in order to withdraw the uppermost sheet 32 of such stack 29 the piston member 12 is displaced obliquely downwards towards the lower end of the cylinder 13 by introduction of compressed air or a pressurized fluid medium, so that the suction cups 9 come to bear upon the uppermost sheet 32, as best shown in FIGURE 2. Further, it should be appreciated that all of the suction cups 9 which are provided at the cross-beam 8 are connected to a common air conduit, and by virtue of removal of air these suction cups 9 adhere to the uppermost sheet 32. The latter is somewhat separated from the remainder of the stack 29 by virtue of the action of the previously considered magnets and/or due to the action of the air jets out of the compressed air nozzles. Next, a suitable pressure medium impinges against the face 12a of the piston member 12 which is connected with the piston rod 11 so that the piston member 12 is displaced into the position shown in FIGURE 3, in other words moves towards the right upper end of the associated cylinder 13. Consequently, the guide means 40 in the form of the previously considered quadrangular or quadrilateral guide linkage arrangements displace the cross-beam 8 along a curve. As a result the uppermost sheet 32 is now raised by the suction cups 9 and displaced in the direction towards the pair of transport or withdrawal rolls 3 to such an extent that it is engaged by the latter and removed from the remainder of the stack 29. This sheet 32, for instance a sheet metal plate, can then be placed upon a table 33, at which location this sheet 32 is further processed or conveyed to another desired location. Owing to the parallelogram guiding of the cross-beam 8 by means of the quadrilateral guide linkage arrangements 40 the undersides of the suction cups 9 always remain parallel to the uppermost sheet 32 of the stack 29, also in the position of the equipment shown in FIGURE 3. At the moment that the raised sheet metal plate 32 is seized by the pair of transport rolls 3 air is admitted into the non-illustrated suction conduit leading to the cross-beam 8, so that the suction cups 9 disengage from the previously held uppermost sheet 32. The latter then falls back onto the stack 29 and bears upon such, yet is withdrawn in sliding fashion over such stack since it is seized by the transport rolls 3, 4.

It will be recognized that in the arrangement of FIG- URE l the suction cups 9 are disposed at the forward edge of the stack 29 in other words at the location A which is considered the front of the machine, since here it is possible to carry out in the simplest and quickest manner the raising of the uppermost sheet 32. Additionally, by virtue of this arrangement it will be appreciated that the suction cups 9 can be pivoted back from the position of FIGURE 3 into the position of FIGURES 1 and 2 even when the previously withdrawn uppermost sheet still bears upon the right hand portion of the stack 29 of FIGURE 2 and is still engaged by the transport rolls 3, 4.

Owing to the removal of the individual sheets 32 the height of the stack 29 will decrease. The table means 25 is therefore moved upwardly, by a known elevating or lifting mechanism, by an amount equal to the degree of such reduction in the stack height. The control of this movement of the table means 25 can, for instance, take place such that after the stack height has decreased an amount equal to about 2 to 4 millimeters the table means 25 is then raised by such amount. When all of the sheets of the stack 29 have been removed then the table means 25 is moved downwardly and is again in position ready to receive a new stack 29.

Instead of using a lifting device with a linearly displaced piston it would also be possible to employ a rotary piston assembly. Furthermore, in lieu of a guide means formed of parallelogram rod or linkages which defiine the quadrilateral guide linkage arrangements, it would also be possible to select a guide linkage arrangement which imparts a slight inclination to the suction cups in the elevated position.

While there is shown and described a present preferred embodiment of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

1. Apparatus for feeding individual sheets from a stack of such sheets to a processing machine, comprising:

a plurality of lifting means for the sheets disposed above said stack;

at least two transport rolls arranged downstream of said stack in the direction of withdrawal of the individual sheets therefrom, said sheets being movable between said transport rolls;

a cross-beam mounted to be longitudinally displaceable at which are arranged said sheet lifting means; power-driven guide means cooperating with said crossbeam for displacing said sheet lifting means;

said sheet lifting means during such displacement conjointly carrying out a substantially curve-shaped work stroke composed of a vertical component and a horizontal component, the uppermost sheet of the stack arriving between said transport rolls at the end of said work stroke.

2. Apparatus for feeding individual sheets from a stack of such sheets to a processing machine as defined in claim 1, wherein said guide means comprises substantially quadrangular guide linkage arrangements.

3. Apparatus for feeding individual sheets from a stack of such sheets to a processing machine as defined in claim 2, wherein said sheet lifting means are defined by suction cup members to which there can be delivered a controlled infeed of air.

4. Apparatus for feeding individual sheets from a stack of such sheets to a processing machine as defined in claim 2, wherein each of said substantially quadrangular guide linkage arrangements is composed of linkage means arranged in substantially parallelogram configuration.

5. Apparatus for feeding individual sheets from a stack of such sheets to a processing machine as defined in claim 2, wherein said sheet lifting means are arranged at the region of the edges of the sheets facing away from said transport rolls.

6. Apparatus for feeding individual sheets from a stack of such sheets to a processing machine as defined in claim 2, further including drive means for said sheet lifting means, said drive means comprising at least one fluid actuated lifting device to which there can be delivered a controlled pressurized medium.

7. Apparatus for feeding individual sheets from a stack of such sheets to a processing machine as defined in claim 6, wherein said drive means operably acts upon said guide means.

8. Apparatus for feeding individual sheets from a stack of such sheets to a processing machine as defined in claim 6, wherein said drive means comprises a piston and cylinder arrangement.

9. Apparatus for feeding individual sheets from a stack of such sheets to a processing machine as defined in claim 8, wherein said piston and cylinder arrangement are pivotally mounted.

References Cited UNITED STATES PATENTS 2,145,764 12/1939 Goebel 27l26 3,070,367 12/1962 Schwebel 27l26 3,370,845 2/1968 Newcomb 27l26 RICHARD E. AEGERTER, Primary Examiner US. Cl. X.R. 

